Grease separator for kitchen sinks and other applications

ABSTRACT

An oil/grease separator separates a lighter liquid from a mixture of the heavier liquid and a lighter liquid. A housing has an inner volume, an inlet to receive influent flow, an outlet to discharge the heavier liquid, which defines a static liquid level, and an outlet port above the static liquid level to discharge substantially all of the lighter liquid and portions of the heavier liquid. The lighter liquid floats on the heavier liquid, so that large volume flows into the inlet raises the liquid level in the housing, flowing the floating lighter liquid through the outlet port.

BACKGROUND OF THE INVENTION

The invention concerns an apparatus for separation of oil/grease andsolid waste material from an effluent flow from a sink, permitting thepassage of grey water to a sewage line.

Over the past thirty years there has been a move towards requiringfood-handling facilities to have sufficient systems for servicingkitchen grease and solid waste bearing water flows. One of the largestproblems, in terms of sewer system lines clogging, has been the oils andgrease put into the sewer system from food handling facilities. Theseproblems and the increase of the severity of the situation in the recentpast has led more and more sewer authorities to implement fats, oils,grease and solid waste control programs. The object of many of theseprograms is to ensure that food handling facilities remove as much aspossible of the oil/grease and solid waste from the effluent flow,thereby releasing only grey water and solids into the sewage system.

Oil/grease and solid waste containment removal for recovery systems arewell known in the prior art. One method recognized in the prior artaccomplishing such removal is an apparatus containing one or morerotating disks formed of a plastic or like material to which oil andgrease contaminants are attracted. Typically, the rotation of the diskin at least partially immersed condition allows the oil to cling thedisk, so that the oil and grease is removed from the body of the waterupon rotation of the disk. A scraper is typically used to force the oiland grease contaminants from the opposite sides of the disk and channelsuch contaminants into a storage collection unit.

The above-mentioned types of devices are assembled within rigidcontainers and the rotating disks are in fixed positions. The scraperassemblies are also in fixed rigid positions. This makes servicing ofthe apparatus difficult, particularly since the parts to be servicedhave been covered in grease and oil. In addition, the units may havebeen permanently installed in a plumbing system so field service isrequired. Because of the nature of installation, the field service isdifficult.

Accordingly, there is a need in the art for a new apparatus forseparation of oil and grease from wastewater that is simple in designand that needs little service. The apparatus should have easilyreplaceable parts for easy field servicing. In addition, there is a needin the art for a low cost apparatus that does not require significantcapital outlay.

SUMMARY OF THE INVENTION

The present invention fulfills one or more of these needs in the art byproviding an oil/grease and solid waste removal apparatus which is lowin cost, easy to maintain and easy to install. The apparatus isolateslighter liquid from a mixture of the heavier liquid and a lighter liquidwith which the lighter liquid is immiscible. A housing has an innervolume with an inlet into the volume to receive an influent flow of amixture of the heavier liquid and the lighter liquid. A first outletfrom the volume to discharge the heavier liquid is positioned such thatthe first outlet defines a static liquid level in the housing and asecond outlet is positioned in the housing so substantially all of thelighter liquid held in the volume can flow through the second outlet,which may be above the static liquid level in the housing. As surges ofinfluent flow are received in the housing and temporarily raise theliquid level above the static liquid level, lighter liquid on top of theheavier liquid in the volume is discharged through the second outlet,together with portions of the heavier liquid. A storage vessel receivesthe liquids from the second outlet. The second outlet may act as areturn path from a low portion of the storage vessel to the housing toreturn heavier liquid from the storage vessel to the housing. Thelighter liquid in the housing tends to float on the heavier liquid inthe housing, so that transient large volume flows into the inlet of thehousing have minimal tendencies to disturb the lighter liquid andtherefore do not cause a substantial discharge of the lighter liquidwith the heavier liquid through the first outlet.

The apparatus may include a sink having a drain connected to the inletat the bottom of the sink housing. The inlet discharges downwardly intothe housing.

In a preferred embodiment, an outer tank serves as the storage vessel.An inner tank has the inlet, which discharges downwardly into the innertank. The inner tank is preferably made of roto-molded plastic and hasmultiple chambers with varying heights from the inlet to the firstoutlet. The multiple chambers of the inner tank promote a rise and fallof liquid within the inner tank caused by large volume flows when theconnected sink is emptied. This flow of fluids aids the oil and greaseto rise to the top of a liquid column within a chamber of the innertank.

The inner tank preferably includes a solid waste removal chamber thatreceives the effluent flow containing solid waste from the connectedsink through the inlet. The solid waste removal chamber has an internalbaffle between the inlet and the outlets and the internal baffleincludes a screen to prevent the downstream movement of solids. Theinternal baffle with the screen traps solid waste material from theeffluent flow within the solid waste chamber. The solid waste chamber isconnected to a solid waste transporter, which may be an eductor. Theeductor creates suction upstream of the internal baffle and screen andis connected to the first outlet. The first outlet is typicallyconnected to the sewage system, so suction created by the eductortransports the solid waste material through the outlet into the sewagesystem.

The inner tank further includes an oil separation chamber and aneffluent separation chamber. The oil separation chamber has a heightthat is higher than the static fluid level in the tank and has thesecond, oil discharge outlet. Preferably, the oil separation chamber hasa high point for the inner tank, so the lighter liquid (oil/grease)migrates to that high point near the oil/discharge outlet. The effluentseparation chamber is connected to the first outlet and includes a damor weir. When liquid levels are below its height, the dam acts as a dam,and as levels rise, it acts as a weir. The dam has a weep slot or hole.The bottom of the slot or hole defines the static liquid level in theinner tank.

The storage vessel receives the oil from the inner tank and in apreferred embodiment is comprised of the space between the inner tankand the outer tank. The outer tank may be constructed of roto-moldedplastic and has a port through which the first outlet extends to removegrey water to the sewage system. The outer tank includes a valve whichmay be manually operated or connected by way of a pump. This valve orpump enables the flow of separated oil from the oil storage vessel. Inanother embodiment the oil storage vessel includes a sensor whichindicates the oil and water level within the storage vessel and signalswhen the oil within the storage vessel reaches a level which requiresoil drainage. The outer tank typically includes a cover constructed ofroto-molded plastic. The outer tank may contain a heater which mayeither be manually or electrically activated and keeps the separated oiland grease in a flowable state.

The oil/grease separator receives effluent flow when the attached sinkis emptied. The oil separation chamber receives the mixture of heavierand lighter liquid. The solid waste may be periodically removed by theeductor within the solid waste removal chamber. The heavier liquid istypically water and the lighter liquid is typically oil and grease. Theoil and grease rises to the top of the fluid mixture by gravity withinthe oil separation chamber with each sink drainage cycle. The oil andgrease flows out of the inner tank through the oil discharge outlet ofthe oil separation chamber, into the storage vessel as the fluid mixturerises during the sink drainage cycle. The oil and grease mixture flowingout of the oil discharge outlet may contain significant amounts ofwater.

The transfer could actually be 100% water. Essentially, the samequantity of fluid moves both ways. If one pint of water/grease/oiltransfers to the storage vessel, then one pint of water will return tothe inner tank. If there is no grease in the inner tank this transfer ofone pint will still take place. But, since any grease/oil in the outertank rises to the top of that tank, only water is transferred back fromthe bottom of the outer tank.

The surges of influent flow caused by the drainage cycle of the sinkcreate a range of fluid flow velocities. This range of fluid flowvelocities includes a low flow rate and a high flow rate. The effluentseparation chamber receives water flow from the oil/grease separationchamber during a sink drainage cycle, typically from a low passage, sothat the oil/grease that has risen does not accompany this flow. Thehigh flow rate caused by the sink drainage cycle causes the water levelto rise in the effluent separation chamber until it flows over the damand through the first outlet into the sewage system. As the water levelsubsides, it drains to the first outlet through the weep slot or hole.During low flow rates, the removal of water by the weep slot permitsflow without significantly raising the liquid level in the oilseparation chamber. As the flow decreases until the effluent no longerpasses over the weir, water escapes from the weep slot/hole. The waterlevel in the inner tank decreases until it reaches the bottom of theweep slot/hole. The liquid level in the oil storage tank also decreases,until it reaches the higher of the bottom of the weep slot/hole or thebottom of the second outlet. The relative heights of those two bottomscan be varied within the scope of the invention.

Another embodiment of the apparatus may include an exterior oil/greasestorage tank which is connected to the oil and grease outlet. Thisexterior oil/grease storage tank has a discharge valve and a greasesensor. The grease sensor signals when the oil/grease storage tankrequires service. The oil/grease storage tank further includes a returnflow path connected to the housing. The flow path is located at thebottom of the oil/grease storage tank and includes a check valve thatprevents flow from the housing to the oil/grease tank through the returnflow path, but permits the flow of water back into the housing.Essentially, the same quantity of fluid moves both ways. If one pint ofwater/grease/oil transfers to the storage vessel, then one pint of waterwill return along the return flow path. If there is no grease in the oilseparation chamber, this transfer of one pint will still take place.But, since any grease/oil in the storage tank rises to the top of thattank, only water is transferred back from the bottom of the storagetank.

Retained oil and grease in the oil separation chamber is forced throughthe oil and grease outlet into the oil and grease storage tank by highwater flows caused by the sink drainage.

The oil/grease separator may include a weir located in the oil/greaseextraction chamber. The weir is tubular and may be plastic with anoutwardly flanged lip at the top of the weir. The height of the weir isset to extend slightly above the water level at maximum expected flow.The weir communicates with the oil and grease outlet within the housing.

The oil/grease separator may include an oil pump which is located in theoil and grease extraction chamber and pumps oil and grease from the topof the fluid column into the oil and grease storage tank.

The oil/grease separator may include a central control module comprisinga grease pump controller, an eductor controller, a grease pump solenoid,an eductor solenoid and three sensors. The central control moduleactuates functions based on signals received from the sensors. Thegrease pump controller engages or disengages the grease pump solenoidbased on signals received from the sensors. The eductor controllerengages or disengages the eductor by activating the eductor solenoidbased on signals received from the sensors.

The oil/grease separator may include a protective cover constructed ofstainless steel sheets which are welded or bolted together.

These and other aspects of the present invention will become apparent tothose skilled in the art after reading the following description of thepreferred embodiments when considered with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by a reading of the DetailedDescription of the Preferred Embodiments along with a review of thedrawings, in which:

FIG. 1 is a schematic sectional drawing of an embodiment of theinvention;

FIG. 2 is a schematic sectional drawing of an embodiment of theinvention including the solid waste removal eductor;

FIGS. 2A and 2B show alternate solid waste transporter embodiments;

FIG. 3 is a front perspective view of the inner tank;

FIG. 4 is a front elevational view of the outer tank and FIG. 4A is aside elevational view of the outer tank;

FIG. 5 is a front view of the outer tank with the outer cover;

FIG. 6 is a schematic drawing of the oil release member with the oillevel sensor;

FIG. 7 is a sectional view of the dam and weep slot;

FIG. 7A is a sectional view of a dam and weephole;

FIG. 8 is a front perspective view of an alternate embodiment;

FIG. 9 is a rear prospective view of the embodiment of FIG. 8;

FIG. 10 is a top view of another alternate embodiment showing thecentral control module;

FIG. 11 is a top perspective view of the weir and oil pump of theembodiment of FIG. 10;

FIG. 12 is a schematic drawing showing the function of the centralcontrol module; and

FIG. 13 is a front view of the protective cover of the alternateembodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following description, like reference characters designate likeor corresponding parts throughout the several figures. It should beunderstood that the illustrations are for the purpose of describingpreferred embodiments of the invention and are not intended to limit theinvention thereto.

As best seen in FIGS. 1 through 3, an embodiment of the oil/greaseseparator 10 includes an inner tank 12, an outer tank 14, an inlet 16and an outlet 28. The oil/grease separator 10 is typically connected toa sink (not shown). However, other sources of effluent such as machinetools or the like can also be serviced. Together, these sources arereferred to herein as “sinks.” The sink drain is connected to the inlet16 and discharges downwardly into the inner tank 12. The inner tank 12is preferably made of roto-molded plastic and comprises multiplechambers with varying heights from the inlet 16 to the outlet 28. Themultiple chambers within the inner tank 12 promote a significant riseand fall flow of fluid level, which is caused by any input volume flowgreater than the weep slot/hole escape volume flow. This fluidseparation process of the invention is applicable to any input sourcethat provides intermittent flows. The flow of fluid aids the oil andgrease within the fluid mixture to rise to the top of the fluid columnwithin the oil separation chamber 13 of inner tank 12. The oil/grease islighter than water and rises to the top of the fluid column by the forceof gravity.

The inner tank 12 includes a solid waste removal chamber 18. The solidwaste removal chamber 18 has an internal baffle 22, which is positionedbetween the inlet 16 and the outlet 28. The internal baffle 22 typicallyincludes a screen 24. The internal baffle 22 and the screen 24 trapsolid waste material from the effluent flow within the solid wasteremoval chamber 18. During a flow of water from the sink (not shown)through inlet 16 caused by empting the sink, the solid waste material istrapped within the bottom chamber 18 by the internal baffle 24. Thesolid waste removal chamber 18 and the oil separation chamber 32 areseparated by the baffle 24 and screen 22.

As seen in FIG. 2 a solid waste transporter 26 is connected to the solidwaste removal chamber 18 and discharges downstream of the chamber 47.This solid waste transporter 26 may be an eductor as disclosed in U.S.Pat. No. 6,491,830 to Batten, et al. entitled “Kitchen Grease RemovalSystem,” the entire disclosure of which is incorporated herein byreference. It can also be a grinder pump as disclosed in U.S. Pat. No.5,360,555 to Batten entitled “Solids Handling in an Oil/greaseSeparator,” the entire disclosure of which is incorporated herein byreference. The eductor embodiment has a jet of water that creates asuction effect in the solid waste removal chamber 18 to transport solidsto the outlet 28 and then to the sewage outlet as may be appropriated,the sewage outlet could be a septic tank.

In another possible variation seen in FIG. 2A, the eductor may beprovided with a separate chamber 300 having a vent hole at its top,selectively opened or closed by a solenoid 302 or other valve. Acompressed air source 304 opens to the top of the chamber. Duringperiods of when the eductor is not in operation, the valve 302 is open,allowing water to flow into the chamber along a low drain line 303 pastcheck valve 306. Since the connection is to the bottom of the outerchamber, the heavier liquid—water—is what flows to the chamber 300, notoil/grease. When eductor operation is needed, the valve 302 is closedand compressed air is admitted to the top of the chamber past valve 305.Once the pressure has reached a desired level, solenoid eductor valve312 is opened, forcing the collected water back out through the jet 310at high velocity, creating the desired eduction effect. When the eductorcycle is through, the valve 312 closes, the pressurized air is turnedoff and valve 302 re-opens to begin a new cycle. This is a particularlyuseful installation where potable water conservation is desirable.Alternatively, the water line with the check valve 302 could receivewater from various points where grey water can be sourced.

A further solid waste transporter option is seen in FIG. 2B. An impeller402 is positioned in the solid waste removal chamber 18 and connected bya shaft 404 to cause the impeller to be driven by a macerator pump motor406. The pump motor 406 is periodically actuated, such as by a timer, tomacerate solids in the chamber 18 and impel them along with waterthrough the discharge pipe 426 to the outlet 424 connected to the drain.

The inner tank 12 includes an oil separation chamber 13. The oilseparation chamber 13 has a height that is higher than the static fluidlevel within the inner tank 12. This height typically is higher thanmost of the inner tank, to concentrate or focus the oil/grease inchamber 13. The static fluid level in the inner tank is defined by thebottom of a weep slot or hole 52 (see FIGS. 7 and 7A) in the outlet 28.The oil separation chamber 13 also has an oil discharge outlet 36 thatremoves oil and water from the inner tank 12 and transfers the oil intothe oil storage vessel 46. The top of the chamber 13 is preferablyvented, with a replaceable lid, so that it can be serviced, if needed,and so it remains at atmospheric pressure, along with the ullage ofouter tank 14.

The inner tank 12 further includes an effluent discharge chamber 42connected to the chamber 13 through a lower passage 33, which minimizesthe lighter liquid's ability to move to the chamber 42. The effluentdischarge chamber 42 includes a dam 44 and a weep slot or hole 52, whichis best seen in FIGS. 7 and 7A. The effluent discharge chamber 42 isconnected to the outlet 28. High volume flows of grey water spill overthe dam 44, through the outlet 28, into the sewage system (not shown).During periods of lower flow, the grey water level does not rise overthe dam, but can flow out through the weep slot or hole 52.

Referring now to FIGS. 3, 4, 4A, and 5, the outer tank 14 is preferablyconstructed of roto-molded plastic. Other materials and methods can beused such as injection molding, metal stamping or other techniques. Thespace between the outer tank 14 and the inner tank 12 comprises thestorage vessel 46. The storage vessel 46 receives the oil and some waterfrom the inner tank 12. The outer tank 14 has inlet 16 and outlet 28protruding through it but communicating only with the inner tan, not theouter tank. The outer tank 14 includes a valve 50, which is a manuallyoperated. The valve 50 permits the drainage of the oil storage vessel 46to an external container (not shown). As seen in FIGS. 4 and 4A, thevalve 50 takes the form of an L-shaped tube with the longer portion ofthe L 53 outside the tank 46. The shorter leg extends into the tank 46through seals in which the shorter leg can rotate. And, the shorter legpreferably extends into the tank at about a 45° angle to the primaryfront plane 49 of the tank. This angle causes the longer leg 53 to moveaway from the plane 49 as it is rotated down, to drain into the externalcontainer. When the leg 53 is turned down, the grease can flow out ofthe shorter leg through the longer leg 53 into the external containerand continue until the longer leg is turned back up, or the oil/greasehas drained down to the shorter leg's height on the plane 49.

Referring now to FIG. 6, the outer tank 14 may include a sensor 48. Thesensor 48 indicates the height of the oil and water within the storagevessel 46 and signals when the oil within the storage vessel 46accumlates to the point that drainage through the valve 50 is needed.Alternatively as seen in FIG. 6A, the sensor 48 can activate a pump 47,or it can provide a signal for an operator to manually operate oractivate a pump.

The outer tank 14 further includes a cover 51, which is preferably madeof roto-molded plastic. The outer tank 14 further includes a heater 38which may be manually or electrically activated. The heater 38 heats theseparated oil and grease to maintain them in a flowable state.

In operation, the oil/grease separator 10 receives an effluent flow fromthe attached sink (not shown). The sink may have a low flow rate,depending on the nature of the use to which it is put. However, in atypical kitchen sink, especially for commercial kitchens, a sink full ofwater used to wash dishes is typically drained at one time, one or moretimes a day, causing a large flow of water and accompanying oil/greaseand solids. The effluent flow contains solid waste material which isretained in the solid waste removal chamber 18 and removed to the sewagesystem (not shown) by the periodic actuation of the solid wastetransporter 26. The fluid mixture comprising a heavier liquid and alighter liquid flows into the oil separation chamber 13. Once the fluidmixture is in the oil separation chamber 13, the lighter liquid rises tothe top of the fluid column by gravity. Furthermore, the combined heightof the two fluids rises within the oil separation chamber 13 with eachlarge volume flow, typically a sink's drainage cycle, as the inflow rateexceeds the rate of drainage through the weep hole/slot 52. Theoil/grease, which is at the top of the fluid mixture, continues to riseuntil it flows out of the oil discharge outlet 36, into the oil storagevessel 46. The oil/grease mixture flowing into the oil storage vessel 46from the oil discharge outlet 36 may contain significant amounts ofwater.

The effluent discharge chamber 42 receives grey water flow from the oilseparation chamber 13 during low flows and during the sink drainagecycle. The high flow rate caused by the sink drainage cycle causes thewater level to rise in the effluent separation chamber 42 until it flowsover the dam 44 through the outlet 28 and into the sewage system (notshown). The system has been described in connection with intermittenthigh flow rates from sinks, such as kitchen sinks, but the inventionalso works well in other installations that generate intermittent largevolume flows.

The weep slot 52, as best seen in FIG. 7 (or as a hole seen in FIG. 7A),discharges water from the effluent separation chamber 42 during high andlow fluid flow rates. During relatively low flow rates, the weep slot orhole 52 permits low flow without significantly raising the water levelin the oil separation chamber 42. The inner tank 12 is connected to theoil storage vessel 46 by the oil discharge outlet 36 in the oilseparation chamber 13. As the flow rate declines at the end of eachdrainage cycle, the fluid level in the oil separation chamber 13 dropsuntil it reaches the bottom of the weep slot or hole 52 in the effluentseparation chamber 42. As the fluid level in the oil separation chamber13 falls to the bottom of the weep slot or hole 52, the fluid level inthe storage vessel 46 falls with it. Water in the vessel 46 flows fromthe bottom of the oil storage vessel 46 into the oil separation chamber13 through the oil discharge outlet 36 until the fluid levels in the oilstorage vessel 46 drops to the level equal to the bottom of dischargeoutlet 36. The fluid level in the inner tank 12 drops to a level justbelow the weep slot or hole 52, and this fluid level represents thestatic fluid level of the inner tank. The fluid levels within the innertank remain substantially at the static level until the start of eachlarge flow, such as a sink drainage cycle. In other embodiments (notshown) the outlet 36 may have a low point below the bottom of the weephole/slot, in which case the static fluid level in the inner tank alsoprevails in the outer tank 14.

Since oil/grease floats on water, it is often the last component flowingfrom a sink in a sink drop, and a concentration of it from a prior sinkdrop is therefore often present in the inlet 16 between sink drops. Asseen in FIG. 1, at the beginning of a sink drainage cycle, the waterlevel in the chamber 42 rises above the dam or weir 44, with anattendant rise in the water level by the height Δ₁ throughout the innertank, before becoming free flowing over the weir and out the outlet 28.This rise throughout the inner tank inhibits an initial high volume flowthrough the passage 33, despite the fact that there is likely an inrushat inlet 16. That inrush causes the oil/grease concentration to flow outof the inlet 16 early in the next sink drop. But the slower flow throughthe passage 33 gives the concentration time to move into the oilseparation chamber 32 and rise above the passage 33, so it does not flowthrough passage 33 once the water flows freely over the weir. Moreover,if the eductor has run since the last sink drop, the water level wouldhave been pulled to a lower level in the chamber 18, to give an evenlarger volume with a vertical dimension of, for example, Δ₂ to fillbefore generating a substantial current through passage 33. Using thisapproach, oil/grease removal efficiencies of 98-99% can be achieved.

In an alternate embodiment as best seen in FIGS. 8 and 9, an oil andgrease separator 110 includes a housing 112, a sink inlet 114, an oiland grease outlet 122, a ceiling 124 over the housing, a sewage outletline 120, and an oil and grease storage tank 126. The bottom of thesewage outlet line 120 generally defines the static water level of theapparatus, since a water level higher than the bottom of the line drainsthrough the outlet 120. The oil and grease separator 110 is connected toa sink 116 having a drain connected to the sink drainpipe 128. The sinkdrainpipe 128 discharges through the sink inlet 114 downwardly into thehousing 112.

The housing 112 has multiple chambers, including bottom chamber 134,second chamber 146 and discharge chamber 147. The multiple levelchambers promote a significant rise and fall of fluid level to aid theoil and grease to rise to the top of the column of water within thesecond chamber 146. This rise and fall of fluid level is promoted bylarge volume flows when the connected sink 116 is emptied. Once the flowis in the housing 112, the oil/grease in the chamber 146 rises to astratum above the water under the influence of gravity. The sewageoutlet 120 is connected to discharge chamber 147, which is connectedthrough a lower passageway 149 to the second chamber 146.

A slot 119 opens upwardly between chamber 134 and chamber 146. The slotpermits the downward installation of a screen to prevent the movement ofsolids from chamber 134 into chamber 146. As seen in FIG. 9, an eductor138 has an inlet to the chamber 134 to permit the transport of solidsfrom chamber 134 to the sewage line, as described above.

The oil and grease storage tank 126 includes an oil and grease dischargevalve 142. The maximum height of the volume of liquid in the tank 126 isdetermined on a static basis by the height of the outlet 120 or the topof line 128, whichever is higher. Over time, the quantity of oil/greasein the tank 126 increases, pushing the boundary between oil/grease aboveand water below, downward. A return flow path 148 connects the bottom ofthe oil and grease storage tank 126 to the second chamber 146. Thisreturn flow path 148 also includes a check valve 150 that prevents waterflow to the oil and grease storage tank 126 from the housing 112 throughthe return flow path 148. A grease sensor 144 is attached to the oil andgrease storage tank 126 to indicate when the oil and grease in the tank126 drops to the level of the sensor. The sensor 144 indicates that theoil and grease storage tank 126 is at capacity for the storage ofoil/grease and requires emptying to prevent return of oil/grease throughreturn line 148.

The second chamber 146 receives effluent water containing oil and greasefrom the bottom chamber 134 and the oil/grease collects under theceiling 124. The ceiling 124 preferably slopes so that a high portion ofit is adjacent the outlet 122, which is connected to the oil and greasestorage tank 126 and has a check valve to prevent return flow from thetank 126. Because it is lighter, the oil and grease rises to the top ofthe second chamber 146 and resides under the ceiling 124. The volume ofwater received in the housing 112 when the sink 116 is emptied causes amomentary rise in the water level above the outlet pipe 120. This risein water level causes the oil and grease to flow into the oil and greasestorage tank 126 through the oil and grease outlet 122, causes the greywater to pass through the passageway 149 from the second chamber 146through the chamber 147 and outlet 120 into the sewage system.

Water is likely to accompany oil/grease as it is transferred to the tank126, but a secondary separation of this water takes place in the tank126, with the separated water returning to the housing 112 through path148.

Referring now to FIGS. 10 and 11, a third embodiment can be seen. Thehousing 156 has multiple chambers of varying heights, including apreliminary chamber 158, a second chamber 160 and a grease extractionchamber 174. The multiple level chambers 158 and 160 promote asignificant rise and fall of fluid level within the housing 154. Thisrise and fall of fluid level aids the oil and grease to rise to the topof the column of water. This rise and fall of fluid level event ispromoted by large volume flows when the sink is emptied. Once the flowis in the chamber 154, the oil and grease rises to a stratum above thewater under the influence of gravity.

After the solid waste material has been removed from the liquid flow bybeing trapped it the preliminary chamber, the liquid flow travels intothe second chamber 160. The volume of water received in the housing 156rises in the housing 154 when the sink 116 is emptied, causing the oiland grease to flow into the second chamber 160. Heaters 180 are locatedin the second chamber 160 and the grease extraction chamber 174 tomaintain the oil and grease in a liquid form. These heaters 180 may bemanually turned on or controlled with sensors which provide informationto a control device which turns the heaters 180 on at preset times or asconditions warrant.

FIG. 10 shows a screen housing 199, like the slot of FIG. 8, to receivea screen 198 separating the preliminary chamber 158 from second chamber160. An eductor solenoid 193 directs fresh water through liquid line 195from a municipal supply (not shown) into solids discharge pipe 184 toeduct solids collected in the chamber 158 to the sewer outlet 186. Asolenoid valve 207 closes to prevent return flows on the liquid linewhen the eductor is not in operation. Solid waste transporterembodiments discussed previously can be used if suitable.

As seen in FIG. 11, a weir 218 is located in the grease extractionchamber 174 within the housing 154. The weir 218 is made of tubularplastic and has an outwardly flanged lip at the top and is adjustablymounted on the intake to the grease outlet 172. The height of the weir218 is adjustable in the grease extraction chamber 174, and ispreferably positioned so that it is above the static water level.Because the height of the weir 218 is set above the height of thehighest water level, only grease and oil will flow into the weir 218 andout the oil and grease outlet 172 into a grease storage tank (notshown). The addition of the weir 218 provides the apparatus with theability to have automatic passive removal of the oil and grease. Theweir is set to extend slightly above the maximum water level in thegrease extraction chamber 174 at the maximum flow rate of water, whichis typically about 20 gallons per minute for a kitchen sink. Because theweir is adjustable, its height can be varied to accommodate othermaximum water heights caused by other flow rates, or by imbalances inthe mounting systems, or the like. As successive flows of fluid arereleased from the sink, the fluid column rises in the oil/greaseextraction chamber 174. The oil/grease rises to the top of the fluidcolumn, and as the oil/grease rises it will flow over the top of theweir 218 through the oil/grease outlet 172 into the storage tank (notshown). The fluid enters the grease extraction chamber 174 through thewater/grease transfer tube 188. The water grease transfer tube 188 alsoprevents the water level in the grease extraction chamber 174 fromexceeding height by permitting excess water to flow back into thepreliminary chamber 158 at the conclusion of a sink dump cycle.

As seen in FIG. 10, a tubing 330 may be provided, connected at one endto the chamber 174 and at the other end through a solenoid 332. Solenoid332 can draw water from the municipal supply and direct it throughtubing 330 to the chamber 174 to raise the liquid level in the chamber174 and cause oil/grease to overflow the weir 218. The municipal supplyis also connected to the eductor.

FIG. 11 shows the tubing connected to an internal transfer tube 322within the housing 174, directed downwardly in cowling 334 so as to forma jet and induce further flow into the housing 174 and to restrict theadded water from simply draining out of the tube 188. Also, by injectingthese downwardly, the oil/grease mat at the top of the chamber 174 isless disturbed, so less water (as distinguished from oil/grease)overflows the weir during such operation. The pump 332 can beselectively controlled in response to a sensor, a timer or manually. Asuitable time for actuation is when there is a drop of effluent from thesink feeding the apparatus, with its attendant rise in liquid levelwithin the apparatus, as a further aid against backflow out of thechamber 174. Preferably, the actuation is in response to conditionssensed by two sensors on the chamber 174. When a lower sensor changesfrom sensing water to sensing oil/grease, the oil/grease mat is thickand actuation of the pump 332 will discharge the oil/grease over theweir. When a higher sensor changes from sensing oil/grease to water, themat has been transferred, so the pump is turned off. Alternatively,instead of the second sensor, the pump may be turned off after theelapse of a period of time.

Referring now to FIGS. 10, 11 and 12, the oil and grease separator 154may further include a central control module 190. The central controlmodule 190 is comprised of a grease pump controller 192, an eductorcontroller 194, a solenoid 204 for the oil grease pump 220, a solenoid206 for the eductor 166, and three sensors 200. The central controlmodule 190 actuates functions based on the signals received from thesensors 200. One of these functions is to open valve 202 via solenoid204 and engage the oil and grease pump 220 to pump oil/grease from thetop of the fluid column in the grease extraction housing 174 into anoil/grease storage tank. The control module 190 opens the oil/greasepump solenoid valve 204, 207 through the oil pump controller 192permitting actuation of the oil/grease pump 220. The control module 190also closes the solenoid 204 for the grease pump 220 by signal to theoil pump controller 192 thereby ceasing grease pumping from theoil/grease extraction chamber 174.

The other function is to initiate solid waste removal by the eductor166. When a sensor 200 senses the presence of fluid (instead of air) itinitiates actuation of the eductor 166 by passing the appropriate signalto the central control module 190. Once the appropriate signal isreceived, the central control module 190 activates the eductorcontroller 194 which opens the solenoid 206 and its valve 168 for theeductor 166, permitting the eductor 166 to remove solid waste from theeffluent flow in the preliminary chamber 158. When the sensor 200 againsenses air, the central control module 190 directs a signal to theeductor controller 194, which closes the solenoid 206 and its valve 168for the eductor 166 thereby stopping the eductor 166 from solid wasteremoval. Various other control schemes can be used.

FIG. 13 shows another embodiment, in which the oil and grease separator110 has a stainless steel protective case 224. The cover is rectangularand is constructed with an inlet pipe 270 from the sink (not shown) asewage outlet pipe 286 and a grease outlet pipe 272. The case 224 isconstructed of stainless steel sheets that are welded together to formthe rectangular case for the unit. The case 224 may also be constructedfrom roto-molded plastic. The stainless steel sheets forming the case224 in this embodiment may also be attached together with nuts and boltsor other fastening means. The protective case 224 provides protectionfrom damage to the oil and grease separator 110.

Certain modifications and improvements will occur to those skilled inthe art upon reading the foregoing description. It should be understoodthat all such modifications and improvements have been omitted for thesake of conciseness and readability, but are properly within the scopeof the following claims.

1. An oil/grease separator to separate a heavier liquid from a mixtureof the heavier liquid and a lighter liquid with which the heavier liquidis immiscible comprising a housing having an inner volume, an inlet intothe inner volume to receive an influent flow of a mixture of the heavierliquid and the lighter liquid with which the heavier liquid isimmiscible, a first outlet from the volume to discharge the heavierliquid positioned such that the outlet defines a static liquid level inthe housing, and a second outlet positioned in the housing sosubstantially all of the lighter liquid held in the volume can flow tothe second outlet and above the static liquid level in the housing, sothat as surges of influent flow are received in the housing andtemporarily raise the liquid level above the static liquid level,lighter liquid on top of the heavier liquid in the volume is dischargedfrom the second outlet, together with heavier liquid, a storage vesselto receive the liquid from the second outlet, and a return path from alow portion of the storage vessel to the housing to return heavierliquid from the storage vessel to the housing, whereby the lighterliquid in the housing tends to float on the heavier liquid in thehousing, so that transient large volume flows into the inlet of thehousing have minimal tendency to disturb the floating lighter liquid andtherefore do not cause substantial discharge of lighter liquid with theheavier liquid through the first outlet.
 2. The apparatus according toclaim 1 further comprising a sink having a drain connected to the inletat a bottom of the sink.
 3. The apparatus according to claim 2, whereinthe inlet discharges downwardly into the housing.
 4. The apparatusaccording to claim 1, wherein the storage vessel is an outer tank inwhich the housing is located.
 5. The apparatus according to claim 4,wherein the housing is made of roto-molded plastic.
 6. The apparatusaccording to claim 4, wherein the housing has multiple chambers withvarying heights.
 7. The apparatus according to claim 6, wherein themultiple chambers promote a rise and fall flow of fluid within thehousing.
 8. The apparatus according to claim 7, wherein the housing isconfigured and the second outlet is positioned to focus the lighterliquid near the second outlet.
 9. The apparatus according to claim 4,wherein the housing includes a solid waste removal chamber.
 10. Theapparatus according to claim 9, wherein the solid waste removal chamberreceives the effluent flow containing solid waste from a connectedsource through the inlet.
 11. The apparatus according to claim 9,wherein a baffle separates the solid waste removal chamber fromdownstream portions of the housing.
 12. The apparatus according to claim11, wherein the internal baffle includes a screen.
 13. The apparatusaccording to claim 12, wherein the internal baffle and screen trapssolid waste material from the effluent flow within the solid wasteremoval chamber.
 14. The apparatus according to claim 12, wherein aneductor creates suction upstream of said internal baffle and screen. 15.The apparatus according to claim 9, wherein the solid waste removalchamber further includes a solid waste transporter.
 16. The apparatusaccording to claim 15, wherein the solid waste transporter is aneductor.
 17. The apparatus according to claim 16, wherein the eductordischarges through the first outlet.
 18. The apparatus according toclaim 17, wherein the first outlet is further connected to the sewagesystem.
 19. The apparatus according to claim 18, wherein suction createdby the eductor transports said solid waste material through the firstoutlet into the sewage system.
 20. The apparatus according to claim 4,wherein the housing further includes an oil separation chamber.
 21. Theapparatus according to claim 20, wherein said oil separation chamber hasa height that is higher than a static fluid level in the housing. 22.The apparatus according to claim 20, wherein the oil separation chamberincludes an oil discharge outlet.
 23. The apparatus according to claim4, wherein the housing includes an effluent separation chamber.
 24. Theapparatus according to clam 23, wherein the effluent separation chamberis connected to the outlet.
 25. The apparatus according to claim 23,wherein the effluent separation chamber includes a dam.
 26. Theapparatus according to claim 25, wherein a high flow rate caused by asink drainage causes the water level to rise in the effluent separationchamber until it flows over the dam through the outlet into the sewagesystem.
 27. The apparatus according to claim 23, wherein the effluentchamber further includes a weep slot.
 28. The apparatus according toclaim 27, wherein during low flow rates the weep slot permits low flowto the first outlet without significantly raising the water leveltowards the second outlet.
 29. The apparatus according to claim 23,wherein said effluent separation chamber has a low passage from the oilseparation chamber to pass water flow from the oil separation chamberduring a sink drainage cycle.
 30. The apparatus according to claim 4,wherein said outer tank is constructed of roto-molded plastic.
 31. Theapparatus according to claim 30, further comprising a protective coverconstructed of stainless steel sheets.
 32. The apparatus according toclaim 31, wherein said stainless steel sheets are welded together. 33.The apparatus according to claim 31, wherein said stainless steel sheetsare fastened together with nuts and bolts or rivets.
 34. The apparatusaccording to clam 4, wherein the inlet extends through a wall in theouter tank.
 35. The apparatus according to claim 4, wherein the outletextends through a wall in the outer tank.
 36. The apparatus according toclaim 35, wherein the outer tank includes a valve.
 37. The apparatusaccording to claim 36, wherein the valve is manually operated.
 38. Theapparatus according to claim 36, wherein the valve regulates the flow ofseparated oil from the outer tank.
 39. The apparatus according to claim35, wherein the outer tank further includes a sensor.
 40. The apparatusaccording to claim 39, wherein the sensor indicates when an interfacebetween the oil and water within the outer tank is below a level. 41.The apparatus according to claim 39, wherein the sensor signals when theoil within the outer tank requires service.
 42. The apparatus accordingto claim 4, wherein the outer tank includes a cover.
 43. The apparatusaccording to claim 42, wherein the cover is constructed of roto moldedplastic.
 44. The apparatus according to claim 4, wherein the outer tankincludes a heater.
 45. The apparatus according to claim 44, wherein theheater is manually activated.
 46. The apparatus according to claim 44,wherein the heater is automatically activated.
 47. The apparatusaccording to claim 44, wherein the heater heats the separated oil tokeep it flowable.
 48. The apparatus according to claim 1, wherein thehousing includes an exterior oil/grease storage tank connected to thesecond outlet.
 49. The apparatus according to claim 48, wherein theoil/grease storage tank further includes a discharge valve.
 50. Theapparatus according to claim 48, wherein the oil/grease storage tankfurther includes a grease sensor to signal that the oil/grease storagetank requires service.
 51. The apparatus according to claim 48, whereinthe oil/grease storage tank includes a return flow path connected to thehousing from a low point of the oil/grease storage tank.
 52. Theapparatus according to claim 51, wherein the return flow path includes acheck valve which prevents flow from the housing to the oil/greasestorage tank through the return flow path.
 53. The apparatus accordingto claim 1, wherein retained oil and grease in the housing is forcedthrough the second outlet into the storage vessel by water flows causedby the sink drainage cycle.
 54. The apparatus according to claim 1,wherein the housing has an oil/grease extraction chamber having a weir.55. The apparatus according to claim 54, wherein said weir is tubular.56. The apparatus according to claim 54, wherein the weir extends abovea water level that prevails after fluid flows into said greaseextraction chamber have stopped.
 57. The apparatus according to claim54, wherein the weir is connected to the storage vessel through thesecond outlet.
 58. The apparatus according to claim 54, wherein the pumpis located in an oil/grease extraction chamber and pumps oil/grease fromthe top of the fluid column into the storage vessel.
 59. An oil/greaseseparator as claimed in claim 1 wherein the housing has a solidsseparation chamber with an eductor pump and a solenoid valve, anoil/grease separation chamber with an oil pump to pump separatedoil/grease and a solenoid valve at the second outlet.
 60. The apparatusaccording to claim 59, wherein said oil/grease separator includes acentral control module.
 61. The apparatus according to claim 60, whereinsaid central control module comprises: a grease pump controller; aneductor controller; a grease pump solenoid; an eductor solenoid; andthree sensors.
 62. The apparatus according to claim 61, wherein saidcentral control module actuates the controllers and solenoids based onsignals received from said sensors.
 63. The apparatus according to claim61, wherein the grease pump controller engages or disengages the greasepump and opens the grease pump solenoid valve based on signals receivedfrom said sensors.
 64. The apparatus according to claim 61, wherein theeductor controller engages or disengages the eductor and opens theeductor solenoid valve based on signals received from the sensors. 65.The apparatus according to claim 1, further including an oil pump. 66.The apparatus according to claim 1, wherein the housing is configuredand the second outlet is positioned to focus the lighter liquid near thesecond outlet.
 67. The apparatus according to claim 1, wherein saidinlet discharges downwardly into the housing.
 68. An oil/greaseseparator to separate a heavier liquid and a lighter liquid with whichthe heavier liquid is immiscible comprising: an outer tank and an innertank, an inlet and an outlet for the inner tank extending through theouter tank; a sink having a drain connected to an inlet of the innertank discharging effluent downwardly into the inner tank; the inner tankhaving multiple chambers comprising; a solid waste removal chamber withan internal baffle and screen trapping solid waste within the solidwaste removal chamber and an eductor connected to the outlet creatingsuction to transport solid waste through the outlet to the sewagesystem, an effluent separation chamber connected to the outlet includinga dam and weep hole or slot defining a static water level; an oilseparation chamber having a height higher than the static fluid leveland including an oil discharge outlet to an oil storage space betweenthe inner and outer tanks; and the outer tank having a cover, a valve toremove separated oil, a sensor to sense when the oil level in the outertank requires service, and a heater to keep separated oil flowable. 69.The apparatus according to claim 1, wherein said heavier liquid is waterand said lighter liquid is oil/grease.
 70. An oil/grease separator toseparate a heavier liquid and a lighter liquid with which the heavierliquid is immiscible comprising: a housing with an inlet and outlet andincluding multiple chambers comprising: a solid waste removal chamberwith an internal baffle and screen to trap solid waste within the solidwaste removal chamber and an eductor connected to the outlet creatingsuction to transport solid waste from the solid waste removal chamberthrough the outlet; an oil extraction chamber including a weir connectedto an oil/grease outlet; an exterior oil/grease storage tank connectedto the oil/grease outlet having a discharge valve, a return flow pathhaving a check valve from a low point of the exterior tank, and anoil/grease sensor; and a grey water discharge chamber downstream of theoil extraction chamber and having the outlet adapted for connection to adrain.